Spacer Chain Research Articles

Editorial: Opportunities in the new service marketplace

PurposeThis paper aims to identify the opportunities in the service marketplace that have arisen because of the changes brought about by the global pandemic (COVID-19).Design/methodology/approachA conceptual methodological approach is used to analyze trends in the history of service research and discuss how articles presented in this issue help scholars and practitioners with planning for opportunities and confronting challenges in the new (post COVID-19) service marketplace.FindingsThis special issue puts forth six viewpoints and seven research articles that outline opportunities in the new service marketplace from regional and global perspectives. Further, the research articles presented in this issue identify four opportunities for managers to consider when designing services in the new service marketplace; these are labeled as reassurance and fear reduction, rethinking physical space and supply chains for multichannel service delivery, the rise of local and community importance and resilience building to combat customer discourtesy.Practical implicationsManagers can understand how the pandemic has profoundly and permanently impacted consumers’ perceptions and expectations for service delivery and processes.Originality/valueThis work presents scholars with a historical overview of trends in service research. The challenges posed by the pandemic represent the beginning of a new era in service research thought and practice as many previously held theories and understandings of consumers’ marketplace behaviors have permanently changed because of behavioral changes that transpired during governmental mandated lockdowns.

On the Configurations of Closed Kinematic Chains in Three-dimensional Space

A kinematic chain in three-dimensional Euclidean space consists of $n$ links that are connected by spherical joints. Such a chain is said to be within a closed configuration when its link lengths form a closed polygonal chain in three dimensions. We investigate the space of configurations, described in terms of joint angles of its spherical joints, that satisfy the the loop closure constraint, meaning that the kinematic chain is closed. In special cases, we can find a new set of parameters that describe the diagonal lengths (the distance of the joints from the origin) of the configuration space by a simple domain, namely a cube of dimension $n-3$. We expect that the new findings can be applied to various problems such as motion planning for closed kinematic chains or singularity analysis of their configuration spaces. To demonstrate the practical feasibility of the new method, we present numerical examples.

Effect of Ca/Si and Al/Si on micromechanical properties of C(-A)-S-H

Calcium silicate aluminate hydrate (C(-A)-S-H) is the main hydration product used in cement-based materials. It plays a specific role in both the mechanical properties and volumetric deformation of the cement matrix. This study aims to clarify the effect of porosity and chemical composition of C(-A)-S-H on its micromechanical properties using nanoindentation. The results showed that porosity significantly affected the indentation, elastic, and creep moduli of the porous C(-A)-S-H compacts. Micromechanical properties of the “pure” C(-A)-S-H were improved by decreasing the Ca/Si ratio. The incorporation of Al slightly altered the creep modulus by affecting the volume of the large gel pores, basal spacing, and mean chain length (if no cross-linking occurred in C(-A)-S-H). Finally, the nanoindentation results of the mixed C(-A)-S-H and Al(OH)3 confirmed the distinct contribution of the individual component characteristics to the overall properties of porous mixtures.

From the Light Chain Sequence to the Tissue Microenvironment: Contribution of the Mesangial Cells to Glomerular Amyloidosis

Studies carried out in the last three decades have significantly advanced our knowledge about the structural factors that drive the amyloid aggregation of the immunoglobulin light chains. Solid-state nuclear magnetic resonance and cryo-electron microscopy studies have resulted in huge progress in our knowledge about the AL fibril structure. Now, it is known that the assembly of the light chain into AL fibrils implies an extensive conformational rearrangement that converts the beta-sandwich fold of the protein into a near flat structure. On the other hand, there has also been significant progress made in understanding the role that some cell types play as facilitators of AL formation. Such a role has been studied in glomerular amyloidosis, where mesangial cells play an important role in the mechanism of AL deposition, as well as for the pathogenic mechanisms that result in glomerular/renal damage. This review addresses what we currently know about why and how certain light chains are prone to forming amyloid. It also summarizes the most recent publications on the structure of AL fibrils and analyzes the structural bases of this type of aggregate, including the origin of its structural diversity. Finally, the most relevant findings on the role of mesangial cells in the amyloid deposition of light chains in the glomerular space are summarized.

Thioether-Linked Liquid Crystal Trimers: Odd-Even Effects of Spacers and the Influence of Thioether Bonds on Phase Behavior.

We report the synthesis, phase-transition behavior, and mesophase structures of the first homologous series of thioether-linked liquid crystal (LC) trimers, 4,4′-bis[ω-(4-cyanobiphenyl-4′-ylthio)alkoxy]biphenyls (CBSnOBOnSCB with a wide range of spacer carbon numbers, n = 3–11). All CBSnOBOnSCB homologs exhibited LC phases. Interestingly, even-n and odd-n homologs showed monotropic layered smectic A (SmA) and pseudo-layered twist-bend nematic (NTB) phases, respectively, below a nematic (N) phase. This alternate formation, which depends on spacer chain parity, is attributed to different average molecular shapes, which are associated with the relative orientations of the biphenyl moieties: linear and bent shapes for even-n and odd-n homologs, respectively. In addition, X-ray diffraction analysis indicated a strong cybotactic N phase tendency, with a triply intercalated structure. The phase-transition behavior and LC phase structures of thioether-linked CBSnOBOnSCB were compared with those of the all-ether-linked classic LC trimers CBOnOBOnOCB. Overall, thioether linkages endowed CBSnOBOnSCB with a monotropic LC tendency and lowered phase-transition temperatures, compared to those of CBOnOBOnOCB, for the same n. This is attributed to enhanced flexibility and bending (less molecular anisotropy) of the molecules, caused by the greater bond flexibility and smaller inner bond angles of the C–S–C bonds, compared to those of the C–O–C bonds.

Improved performance of vanadium redox flow battery with tuneable alkyl spacer based cross-linked anion exchange membranes

We synthesize cross-linked aliphatic polymer with side chain grafted imidazole based anion exchange membranes (AEMs) using alkyl chain spacer. Prepared AEMs exhibit excellent stabilities, ionic conductivity, and vanadium ion impervious nature. These AEMs with rigid polymer matrix show low swelling ratio in spite of high molality of exchangeable functional groups. Cross-linked methylmethacrylate-co-vinyl imidazole copolymer (CMVI) with C3 spacer (CMVI-C3) possess 1.21 meq/g ion exchange capacity, and 8.1 × 10−2 S/cm conductivity. Well optimized CMVI-C3 AEM shows extremely low VO2+ permeability (1.96 × 10−9 cm2 s−1) in comparison to Nafion 117 (16.34 × 10−9 cm2 s−1), due to blocking property of CMVI AEMs for VO2+. At 120.0 mA cm−2, relatively high Coulombic (98.8%), energy (78.2%), and voltage (80.5%) efficiencies of CMVI-C3 AEM in comparison with Nafion 117 membrane, has been attributed to synergetic balance between hydrophobic and hydrophilic segments. The CMVI-C3 AEM maintains the high performance and good integrity during in-situ VRFB cycle performance assessment up to 200 cycles. Simple method for the preparation, good stabilities, and high performance are attractive features of CMVI-C3 AEM for vanadium redox flow battery.

UV-A and UV-B banning highly soluble photocrosslinkable thermotropic liquid crystalline copolyesters with ether linkage in the backbone

Four random copolyesters were synthesized by the polycondensation of a chalcone diol 3-(4-hydroxy-3methoxyphenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (HMPP) with the common diacid, namely, 4,4′-oxybis(benzoic acid) with two varying diacids (terephthalic acid and isophthalic acid) and two varying diols (1,4-dihydroxyanthraquinone and 1,5-dihydroxyanthraquinone). The chalcone diol was synthesized by acid-catalyzed Claisen-Schmidt reaction. These four random copolyesters were synthesized by solution polycondensation technique and were characterized by qualitative solubility tests and viscosity measurements. The monomeric moieties incorporated in the copolyester backbone was established by FT-IR, 1H NMR and 13C NMR spectroscopic techniques. Tg, Tm and Tiso were determined by DSC thermograms and found to be in the range of 59–97 °C, 123–143 °C and 160–252 °C, respectively. The copolyesters displayed nematic phase without involving methylene-flexible spacers in the polymeric backbone. The phase transition was found to be reproducible on heating and cooling above Tm. The photocrosslinking ability was ascertained by recording UV spectra at different time intervals of irradiation of UV light from 150-watts, 365-nm mercury lamp at room temperature in DMF. Herein, for the first time, we report the synthesis and characterization of a series of novel photosensitive liquid crystalline chalcone polymers without spacer chains. In addition to these, density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations have been performed to ascertain the cross-linking nature of the synthesized polymer from computed absorption spectra. All these polyesters exhibit a good photocrosslinking property by absorbing UV-A light. They continue to absorb UV-B light (which is more dangerous to human skin and eyes) after the crosslinking. As these polymers filter UV-A and UV-B rays one after another, a switching system can be evolved from these materials. These polymers exhibit high thermal stability and UV filtering ability at both UV-A and UV-B regions and have good solubility ensuring their application-oriented nature.

New Milan metro-line M4. From infrastructural project to design scenario enabling urban resilience

Resilience is an attitude of a system to cope with shock or stress and to guarantee its continuity. Referring to a city or a neighborhood, a resilient system is an urban body that can sustainably adapt to natural and climate hazards, economic, social, and technological shocks. Moreover, it can sustainably transform solving chronic problems such as traffic, air, and noise pollution.The city of Milan is the case study where trial the re-designing of sustainable, safe, and resilient urban space. The Green-blue backbone project re-shapes a chain of public spaces according to the development of the new metro line M4. The Green-blue backbone is a network of paths and public spaces for pedestrians and cyclists that cross the city center and connect two parks. Its design and implementation are tuned with historic heritage and peripheral neighborhoods and facing their resources through active mobility development. The paper discusses the Masterplan proposal aimed to convert a simple infrastructural project into a well-organized urban space design. Urban design priorities were a high visual appeal, easy and simple maintenance, high ecological function, cultural heritage protection, and sustainable mobility. The Green-blue backbone project pushes Public Administration to re-consider urban space design to implement new local connections and new metropolitan identities according to a sustainable transport system, and to re-think the common background where the community might be resilient. In particular focusing on ecological, functional, and perceptual aspects that are effective elements in creating urban resilience. From an urban planning perspective, Milan’s Green-blue backbone is the opportunity to realize safer and resilient public spaces and sustainable mobility, looking at the time-space design of the public transport and ecological network.

Offshore wind energy potential in Europe: a forecast of installed capacities and costs

Offshore wind installation targets of EU Member States were considered. The analysis of the national plans showed that EU target can be exceeded, provided the appropriate resources are committed: offshore space, capital and supply chain. Spatial plans were analyzed and the need for the number of installed turbines was determined. The capital needs to cover the costs of investment outlays were analyzed. A projection for the number of wind turbines installed in Europe up to 2030 was presented. The analysis identified how the resources committed to the targets will contribute to: the generation of electricity, the reduction in greenhouse gas emissions and contribution to improving Europe’s energy independence.

Albumin-Methotrexate Prodrug Analogues That Undergo Intracellular Reactivation Following Entrance into Cancerous Glioma Cells.

A family of monomodified bovine serum albumin (BSA) linked to methotrexate (MTX) through a variety of spacers was prepared. All analogues were found to be prodrugs having low MTX-inhibitory potencies toward dihydrofolate reductase in a cell-free system. The optimal conjugates regenerated their antiproliferative efficacies following entrance into cancerous glioma cell lines and were significantly superior to MTX in an insensitive glioma cell line. A BSA–MTX conjugate linked through a simple ethylene chain spacer, containing a single peptide bond located 8.7 Å distal to the protein back bone, and apart from the covalently linked MTX by about 12 Å, was most effective. The inclusion of an additional disulfide bond in the spacer neither enhanced nor reduced the killing potency of this analogue. Disrupting the native structure of the carrier protein in the conjugates significantly reduced their antiproliferative activity. In conclusion, we have engineered BSA–MTX prodrug analogues which undergo intracellular reactivation and facilitate antiproliferative activities following their entrance into glioma cells.

Physical-Chemical Characterization of Bilayer Membranes Derived from (±) α-Tocopherol-Based Gemini Lipids and Their Interaction with Phosphatidylcholine Bilayers and Lipoplex Formation with Plasmid DNA.

Membrane formation and aggregation properties of two series of (±) α-tocopherol-based cationic gemini lipids without and with hydroxyl functionalities at the headgroup region (TnS n = 3, 4, 5, 6, 8, and 12; THnS n = 4, 5, 6, 8, and 12) with varying polymethylene spacer lengths were investigated extensively while comparing with the corresponding properties of the monomeric counterparts (TM and THM). Liposomal suspensions of each cationic lipid were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), zeta potential measurements, and small-angle X-ray diffraction studies. The length of the spacer and the presence of hydroxyl functionalities at the headgroup region strongly contribute to the aggregation behavior of these gemini lipids in water. The interaction of each tocopherol lipid with a model phospholipid, 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC)-derived vesicles, was thoroughly examined by differential scanning calorimetry (DSC) and 1,6-diphenyl-1,3,5-hexatriene (DPH)-doped fluorescence anisotropy measurements. The binding efficiency of the cationic tocopherol liposomes with plasmid DNA (pDNA) was followed by an ethidium bromide (EB) exclusion assay and zeta potential measurements, whereas negatively charged micellar sodium dodecyl sulfate (SDS)-mediated release of the pDNA from various preformed pDNA-liposomal complexes (lipoplex) was studied by an ethidium bromide (EB) reintercalation assay. The structural transformation of pDNA upon complexation with liposome was characterized using circular dichroism (CD) spectroscopic measurements. Gemini lipid-pDNA interactions depend on both the presence of hydroxyl functionalities at the headgroups and the length of the spacer chain between the headgroups. Succinctly, we performed a detailed physical-chemical characterization of the membranes formed from cationic monomeric and gemini lipids bearing tocopherol as their hydrophobic backbone and describe the role of inserting the -OH group at the headgroup of such lipids.

Utilising activity space concepts to sampling of alternatives for mode and destination choice modelling of discretionary activities

Choice models estimated on datasets with large numbers of alternatives present significant challenges leading to rapidly expanding computational cost, as well as potential behavioural realism issues. Sampling of alternatives has been a well-established method for overcoming the computational limitations, mostly applied to models of residential location. Nonetheless, destination choice models of discretionary activities require a different type of analysis, since the choice can be governed by time–space constraints and familiarity regarding the alternatives. Observing the general areas of travel for a period of days using high resolution GPS tracking can provide important information of the individuals’ whereabouts. The present study, taking advantage of such a dataset, proposes a more behaviourally realistic sampling protocol to reduce the choice set utilising the geography-based concepts of activity spaces. Differential importance sampling rates are applied depending on the individual’s activity space and trip chain making the resulting sampled choice set a function of person-specific spatial awareness and mode-specific time–space constraints. The performance of the sampling protocol developed is assessed using a model estimated with the full choice set and compared with random sampling and several other importance sampling protocols. The modelling outputs suggest that random sampling should be used with care, since it can result in highly biased estimates, but with low standard errors, as well. The proposed approach incorporates both time–space constraints and individual spatial awareness and is able to produce less biased estimates, achieve higher sampling stability and statistical efficiency, while also avoiding overfitting.

Increasing donor-acceptor spacing for reduced voltage loss in organic solar cells

The high voltage losses ({V}_{{loss}}), originating from inevitable electron-phonon coupling in organic materials, limit the power conversion efficiency of organic solar cells to lower values than that of inorganic or perovskite solar cells. In this work, we demonstrate that this {V}_{{loss}} can in fact be suppressed by controlling the spacing between the donor (D) and the acceptor (A) materials (DA spacing). We show that in typical organic solar cells, the DA spacing is generally too small, being the origin of the too-fast non-radiative decay of charge carriers ({k}_{{nr}}), and it can be increased by engineering the non-conjugated groups, i.e., alkyl chain spacers in single component DA systems and side chains in high-efficiency bulk-heterojunction systems. Increasing DA spacing allows us to realize significantly reduced {k}_{{nr}} and improved device voltage. This points out a new research direction for breaking the performance bottleneck of organic solar cells.

Effect of Lithium-Ion on the Structural Organization of Monocationic and Dicationic Ionic Liquids.

In recent times, ionic liquid-based (ILs) electrolytic system has emerged as suitable alternative to the conventional organic solvent-based electrolytic system. However, since, anion of ILs is known to form aggregates in the presence of lithium-ions (Li+), and this can influence the transport properties of Li+ ion in a significant manner, it is, therefore, important to understand how lithium-ions influence the structure and dynamics of ILs. With this objective, in the present study, intermolecular interaction, structural organization, and dynamics of monocationic ILs (MILs) and dicationic IL (DIL) have been studied in the absence and presence of lithium salt. Specifically, for this purpose, two MILs, 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide ([C3C1im][NTf2]), 1-hexyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide ([C6C1im][NTf2]), and a DIL, 1,6-bis(3-methylimidazolium-1-yl)hexane bis(trifluoromethylsulfonyl)amide ([C6(mim)2][NTf2]2) have been chosen in such a way that either the alkyl chain of MILs becomes equal or half of the spacer chain length of DIL. To understand the effect of the addition of lithium-ion on the structural organization of MILs and DIL, steady-state absorption and fluorescence spectroscopies, time-resolved fluorescence anisotropy and nuclear magnetic resonance (NMR) techniques have been used. Structural organization in the apolar and polar domains of ILs has been probed by following the rotational diffusion of suitably chosen solute in the concerned media through time-resolved fluorescence anisotropy (TRFA) measurements. TRFA studies have revealed that with the addition of Li+ ion, coordination between the Li+ ions and anions of MILs and DILs takes place in the ionic region leading to a change in the structural organization of the apolar regions of the respective medium. In fact, upon adding lithium-ions, a reduction in the packing of alkyl chains has also been observed for the MILs. However, not much change in the structural organization of the apolar region of the DIL has been observed when Li+ ion is added to it. In the presence of Li+ ions, a similar trend in the change of structural organization of polar regions for both MILs and DIL has been observed. Further, measurements of the self-diffusion coefficient through NMR have also supported the observation that Li+ ion also perturbs the nanostructural organization of the MIL in a significant manner than that it does for the DIL. The behavior of DIL in the presence of Li+ ion, as revealed by the present study, has been rationalized by considering the folded arrangement of DIL in the fluid-structure. Essentially, all of these investigations have suggested that the addition of lithium-ion significantly alters the microscopic behavior of MILs in comparison to that of DIL. The outcome of this study is expected to be helpful in realizing the potentials of these media as electrolytes in battery applications.

Synthesis and surface‐active properties of novel cleavable gemini surfactants

AbstractA novel series of quaternary ammonium gemini compounds having a butynylene spacer and different hydrocarbon chain lengths (CGBu8‐16) were prepared. Carbonate group inserted between the hydrocarbon chains and the polar heads make these compounds hydrolyzable. The degradation under hydrolysis of these novel series will lead to the generation of fatty alcohols and readily degradable compounds. The reagents used are biodegradable, renewable, or reusable. The surface activities and foamability in aqueous solution of the cleavable gemini compounds containing n‐octyl, n‐decyl, and n‐dodecyl chains meet the criteria for being good surfactants and showed stable foams even at low concentrations.

A Highly Robust Ionotronic Fiber with Unprecedented Mechanomodulation of Ionic Conduction.

Stretchable ionic conductors are appealing for tissue-like soft electronics, yet suffer from a tardy mechanoelectric response due to their poor modulation of ionic conduction arising from intrinsic homogeneous soft chain network. Here, a highly robust ionotronic fiber is designed by synergizing ionic liquid and liquid crystal elastomer with alternate rigid mesogen units and soft chain spacers, which shows an unprecedented strain-induced ionic conductivity boost (≈103 times enhanced as stretched to 2000% strain). Such a surprisingly high enhancement is attributed to the formation of microphase-separated low-tortuosity ion-conducting nanochannels guided by strain-induced emergence of aligned smectic mesophases, thus allowing for ultrafast ion transport that resembles the role of "swimming lanes." Intriguingly, the boosting conductivity even reverses Pouillet's Law-dictated resistance increase at certain strains, leading to unique waveform-discernible strain sensing. Moreover, the fiber retains thermal actuation properties with a maximum of 70% strain changes upon heating, and enables integrated self-perception and actuation. The findings offer a promising molecular engineering route to mechanically modulate the ion transport behavior of ionic conductors toward advanced ionotronic applications.

Design, Synthesis, and Cytotoxicity Assessment of [64Cu]Cu-NOTA-Terpyridine Platinum Conjugate: A Novel Chemoradiotherapeutic Agent with Flexible Linker.

Maximum benefits of chemoradiation therapy with platinum-based compounds are expected if the radiation and the drug are localized simultaneously in cancer cells. To optimize this concomitant effect, we developed the novel chemoradiotherapeutic agent [64Cu]Cu-NOTA-C3-TP by conjugating, via a short flexible alkyl chain spacer (C3), a terpyridine platinum (TP) moiety to a NOTA chelator complexed with copper-64 (64Cu). The decay of 64Cu produces numerous low-energy electrons, enabling the 64Cu-conjugate to deliver radiation energy close to TP, which intercalates into G-quadruplex DNA. Accordingly, the in vitro internalization kinetic and the cytotoxic activity of [64Cu]Cu-NOTA-C3-TP and its derivatives were investigated with colorectal cancer (HCT116) and normal human fibroblast (GM05757) cells. Radiolabeling by 64Cu results in a >55,000-fold increase of cytotoxic potential relative to [NatCu]Cu-NOTA-C3-TP at 72 h post administration, indicating a large additive effect between 64Cu and the TP drug. The internalization and nucleus accumulation of [64Cu]Cu-NOTA-C3-TP in the HCT116 cells were, respectively, 3.1 and 6.0 times higher than that for GM05757 normal human fibroblasts, which is supportive of the higher efficiency of the [64Cu]Cu-NOTA-C3-TP for HCT116 cancer cells. This work presents the first proof-of-concept study showing the potential use of the [64Cu]Cu-NOTA-C3-TP conjugate as a targeted chemoradiotherapeutic agent to treat colorectal cancer.

Whole genome sequencing of colonies derived from cannabis flowers and the impact of media selection on benchmarking total yeast and mold detection tools.

Cannabis products are subjected to microbial testing for human pathogenic fungi and bacteria. These testing requirements often rely on non-specific colony forming unit (CFU/g) specifications without clarity on which medium, selection or growth times are required. We performed whole genome sequencing to assess the specificity of colony forming units (CFU) derived from three different plating media: Potato Dextrose Agar (PDA), PDA with chloramphenicol and Dichloran Rose Bengal with chloramphenicol (DRBC). Colonies were isolated from each medium type and their whole genomes sequenced to identify the diversity of microbes present on each medium selection. Fungal Internal Transcribed Spacer (ITS3) and Bacterial 16S RNA(16S) quantitative polymerase chain reactions (qPCR) were performed, to correlate these CFUs with fungi- and bacterial- specific qPCR. Each plating medium displayed a ten-fold difference in CFU counts. PDA with chloramphenicol showed the highest diversity and the highest concordance with whole genome sequencing. According to ITS3 and 16S qPCR confirmed with whole genome sequencing, DRBC under counted yeast and mold while PDA without chloramphenicol over counted CFUs due to bacterial growth without selection. Colony Forming Unit regulations lack specificity. Each medium produces significant differences in CFU counts. These are further dependent on subjective interpretation, failure to culture most microbes, and poor selection between bacteria and fungi. Given the most human pathogenic microbes found on cannabis are endophytes which culture fails to detect, molecular methods offer a solution to this long-standing quantification problem in the cannabis testing field.

Whole genome sequencing of colonies derived from cannabis flowers and the impact of media selection on benchmarking total yeast and mold detection tools.

Cannabis products are subjected to microbial testing for pathogenic fungi and bacteria. These testing requirements often rely on non-specific colony forming unit (CFU/g) specifications without clarity on which medium, selection or growth times are required. We performed whole genome sequencing to assess the specificity of colony forming units (CFU) derived from three different plating media: Potato Dextrose Agar (PDA), PDA with chloramphenicol and Dichloran Rose Bengal with chloramphenicol (DRBC). Colonies were isolated from each medium type and their whole genomes sequenced to identify the diversity of microbes present on each medium selection. Fungal Internal Transcribed Spacer (ITS3) and Bacterial 16S RNA(16S) quantitative polymerase chain reactions (qPCR) were performed, to correlate these CFUs with fungi- and bacterial- specific qPCR. Each plating medium displayed a ten-fold difference in CFU counts. PDA with chloramphenicol showed the highest diversity and the highest concordance with whole genome sequencing. According to ITS3 and 16S qPCR confirmed with whole genome sequencing, DRBC under counted yeast and mold while PDA without chloramphenicol over counted CFUs due to bacterial growth without selection. Colony Forming Unit regulations lack specificity. Each medium produces significant differences in CFU counts. These are further dependent on subjective interpretation, failure to culture most microbes, and poor selection between bacteria and fungi. Given the most pathogenic microbes found on cannabis are endophytes which culture fails to detect, molecular methods offer a solution to this long-standing quantification problem in the cannabis testing field.

Ligand size effects in two-dimensional hybrid copper halide perovskites crystals

Intensive effort to tailor photophysics of lead-free perovskites is appealing in recent years. However, their combined electronic and optical property elucidations remain elusive. Here, we report spectroscopic observations of the coexistence Zhang-Rice singlet state and exotic electronic transitions in two-dimensional copper-based perovskites. Herein, several perovskites with different alkylammonium spacers are investigated to unravel their correlated electronic systems and optical responses. Namely, methylammonium, ethylammonium, phenylmethylammonium and phenethylammonium. Using temperature dependent high-resolution X-ray absorption spectroscopy, we observe distinct electronic features highlighting the impact of short spacer chains compared to long-conjugated ligands, demonstrating a pronounced 3d9 and 3d9L signature linewidth variation. Corroborated by density functional theory calculations, the transient dynamics evolution of copper-based hybrid perovskites is influenced by the strong interplay of electron-phonon interactions and geometric constrictions. This finding sheds light on tuning the electronic and optical properties of hybrid perovskites towards efficient photoactive-based devices.